1. Field of the Invention
The present invention relates to an image forming apparatus, an image forming method and a program, which make a density correction for realizing a stable reproducibility of an image in pseudo high-resolution processing.
2. Description of the Related Art
In recent years, progress of a high-quality image in a printer is remarkable, and a high-resolution processing of an engine, a high speed of the processing unit accompanying the high-resolution processing and an increase in memory capacity have rapidly been progressed. However, since enormous costs are required for meeting all of them, several methods are at present proposed for achieving the high-quality image or the high speed and the low costs all together.
An example of a method conventionally performed in a printer of an electronic photo system includes a method where in a low-resolution printer engine, low-resolution image data are exposed on a photo conductor so as to overlap between dot pitches of each pixel (for example, refer to Japanese Patent Laid-Open No. H04-336859(1992). In consequence, latent images are formed so that the overlapped portions between the pixels become also effective pixels. This is called spot multiplexing for reproducing an image with a pseudo higher resolution than an actual resolution.
In the above conventional technology (for example, refer to Japanese Patent Laid-Open No. H04-336859(1992), rendering is made to a high-resolution image data, various types of image processing are performed to the high-resolution image data as it is, and thereafter, it is required to generate and print the low-resolution image data for printing. Therefore, an example of a method of realizing the spot multiplexing at low costs includes a method in which a high-resolution image data is converted into a low-resolution image data and thereafter, various types of image processing are performed to the low-resolution image data, and a pseudo high-resolution image data is reproduced using the spot multiplexing (for example, refer to Japanese Patent Laid-Open No. 2004-201283).
However, since the above spot multiplexing forms the latent image from the overlapping of the two adjacent exposure portions for reproducing one dot, there is a problem that the dot reproduction is unstable and is difficult to control as compared to the usual processing. In particular, it is difficult to reproduce a small character or a thin line, which may be reproduced in such a manner as to be blurred with a light density at best. Therefore, the reproduction stabilization has been achieved by making the density correction so as to increase the density of the character or the whole line, but the spot multiplexing has also an issue that the color appearance of the character or the line largely changes.